The device for altering processing of a signal during processing of the signal can be used in various applications. For instance, the device can be a DJ controller, the signal can be an audio signal, the processing can be a playing back of the audio signal and the altering can be a repeating of a series of pulses or beats of the audio signal. With such a device a DJ can alter tracks live during play-back by selecting a number of beats to be repeated and commanding start and/or end point in time of the repetition.
For enabling a user, e.g. a DJ, to alter the signal processing during processing an input unit and a display unit may be used. The input unit allows for a selection input for selecting the duration of the time period to-be-used for altering processing, and a command input for commanding altering the processing using the time period. The display unit makes it possible to graphically display an interval to-be-processed-next of the signal. After receiving the command input the display unit may be used to display graphically the time period.
For instance, during looping of a continuous series of beats of an audio signal, a transparent overlay indicates within the interval displayed the looped series.